I found that if the point is to let water come together is important, but effective drainage will cause a flood at that point and the other points as acquired.
I found that if the point of the water together in a point that is important, but less effective drainage will cause flooding problems at that point and other points as possible.
It was found that the points are to release the water together is dotted with importance but efficient ventilation น้ำต่ำ will cause flooding point and other points. Have followed.